The device used to fix the processing object in the machine manufacturing process so that it has the correct position to accept construction or testing. Also called fixture. In a broad sense, any process in the process, the device used to quickly, easily and safely install the workpiece can be called a fixture. For example, welding fixture, inspection fixture, assembly fixture, machine tool fixture, etc. Among them, machine tool fixtures are the most common, often referred to as fixtures. When processing the workpiece on the machine tool, in order to make the surface of the workpiece meet the technical requirements such as the size, geometry and accuracy of mutual position with other surfaces, the workpiece must be installed (positioned) and clamped (clamped) before processing. . Fixtures are usually composed of positioning elements (determining the correct position of the workpiece in the fixture), clamping devices, tool guide elements (determining the relative position of the tool to the workpiece or guiding the direction of the tool), and indexing devices (allowing the workpiece to be installed in a single installation) Finished processing at several stations, including rotary indexing device and linear moving indexing device), connecting elements and clamps (fixture base). The types of fixtures can be divided according to their characteristics: ① Universal universal fixtures. Such as machine vices, chucks, indexing heads, and rotary tables, etc., have great versatility and can adapt to the transformation of processing procedures and processing objects. The structure has been finalized, and the size and specifications have been serialized. Most of them have become a standard accessory for machine tools. ② Special fixture. It is specially designed and manufactured for the clamping needs of a certain product part in a certain process. The service object is specific and highly targeted. Generally, it is designed by the product manufacturer. Commonly used are lathe fixtures, milling machine fixtures, drilling dies (machine tool fixtures for guiding tools to drill holes or reaming on workpieces), boring dies (machine tool fixtures for guiding boring bars for boring on workpieces) and accompanying fixtures (for On the automatic line of the combined machine tool). ③ Adjustable fixture. Dedicated fixtures that can be replaced or adjusted. ④ Combination fixture. Fixtures composed of standardized components of different shapes, specifications and uses, suitable for single product, small batch production and temporary tasks of new product trial production and frequent product replacement.
In addition to vise, chuck, indexing head and rotary table, there is a more common tool holder. Generally speaking, when the word tool holder appears at the same time, most of the holder refers to the holder!
Instructions for outfit welding fixture
Operating steps of fixture:
(1) Assemble the two parts of the sequence 4 engine liner to the sequence 1 struts according to the 'strut welding combination' diagram, and place them on the clamp concrete. The sequence 1 struts are positioned by the blocking pins and baffles. The sequence 1 strut is clamped by a screw clamp; at the same time, the two pieces of the sequence 4 engine liner are positioned by a bolt, and clamped by a quick-release screw clamping device.
(2) After spot welding, loosen the quick-release screw clamping device, pull out the bolt, and remove it for welding
(3) Place the weldment on the clamp, position the weldment by the blocking pin and the baffle, and clamp the weldment by the screw clamp; then place the components of the nut M6 and the horn support on the weldment. The taper pin on the screw clamping mechanism and the open groove on the pressure plate of the screw clamping mechanism are used to position and clamp by the screw clamping mechanism.
(4) Three-sided welding of the nut M6 and the component of the horn support and the brace, and then loosening all the screw clamps, the pressure plate of the screw clamping mechanism clamping the components of the nut M6 and the horn support is springed up by the spring Then, the positioning cone-head pin on it is separated from the welding piece, and then the pressure plate is pushed out to release one end from the stud of the screw clamping mechanism, the pressure plate is rotated to the side of the welding piece, and then the welding piece is taken out.
---------, Precautions for use, maintenance and maintenance:
(1) Check whether the limit size is still in the correct position before use;
(2) If the stop pin wears out badly, it can be polished and repaired; if the baffle, latch, and positioning cone pin wear out of wear, it can be reassembled, and it can be used after staggering the wear part.
(3) Apply anti-embroidery oil after use.
26. Summary, experience and suggestions for the design of this course
Most welding tools are specially designed for the assembly and welding process of a certain welding assembly. They are non-standard devices and often need to be designed and manufactured by themselves according to the characteristics of the product structure, production conditions and your actual needs. Welding tooling design is one of the important contents of production preparation and one of the main tasks of welding production process design. For manufacturing industries such as automobiles, motorcycles, and airplanes, it is no exaggeration to say that there are no products without welding tools. Through the process design, the required tooling types, structure sketches and brief descriptions are presented, and the detailed structure and part design and all drawings are completed on this basis.
The quality of tooling design has a direct impact on production efficiency, processing costs, product quality, and production safety. To this end, practicality, economy, reliability, and artistry must be considered when designing the welding tooling.
During the mechanical design and manufacturing process, dimensional chain problems are common. In the process of assembling parts into a machine, that is, combining and accumulating the relevant dimensions on the parts. Due to manufacturing errors in the dimensions of the parts, errors will be synthesized and accumulated during assembly. The total error formed after the accumulation will affect the working performance and quality of the machine. This forms the interaction between the dimensional error and the comprehensive error of the part. Designing fixtures is no exception. It is important to reasonably determine the dimensional and geometric tolerances of a part.
Through the design of this course, not only the systematization of the professional knowledge of welding process equipment is enhanced, but also the professional knowledge, design ability and practical ability are organically combined. The deeper harvest should be to consolidate and broaden the thinking of designing fixtures and to exercise the principles and flexibility of design thinking.